https://link.springer.com/article/10.2478%2Fs11686-019-00058-4 POSTPRINT Description of Piscicapillaria bursata sp. n. (Capillariidae) and redescription of Parascarophis sphyrnae Campana-Rouget, 1955 (Cystidicolidae), two nematode parasites of hammerhead sharks (Sphyrna spp.) off Australia František Moravec · Diane P. Barton __________________________________________________________________________ F. Moravec () Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, Branišovská 31, 370 05 České Budějovice, Czech Republic e-mail: [email protected] D. P. Barton Fisheries Research, Department of Primary Industries and Resources, Northern Territory Government, Berrimah, Northern Territory 0828, Australia; School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales 2678, Australia Abstract: Examinations of two species of hammerhead sharks, Shyrna lewini (Grifith et Smith) and S. mokarran (Rüppel) (Sphyrnidae, Carcharhiniformes), from off the northern https://www.nespmarine.edu.au/document/description-piscicapillaria-bursata-sp-nov-capillariidae- and-redescription-parascarophis Page 1 https://link.springer.com/article/10.2478%2Fs11686-019-00058-4 POSTPRINT coast of Australia revealed the presence of two species of intestinal nematode parasites, Piscicapillaria bursata sp. n. (Capillariidae) and Parascarophis sphyrnae Campana-Rouget, 1955 (Cystidicolidae). The new capillariid species P. bursata sp. n. from S. mokarran (type host) and S. lewini differs from its congeners mainly in the spicule length (330 µm), body length of gravid females 12.80–21.26 mm and in possessing a subterminal female anus. Light and scanning electron microscopical examination of the specimens of P. sphyrnae (type species of Parascarophis Campana-Rouget, 1955), recorded from S. lewini, made it possible to redescribe the female and, for the first time, to describe the male. Amended diagnosis of Parascarophis is provided. Parascarophis is mainly characterized by the presence of lateral alae, a unique feature within the Cystidicolidae, and by the cephalic structures (presence of a cuticular hood and a pair of anterolateral plate-like structures in the mouth). Species of Parascarophis previously described from teleosts, P. bharatii Agrawal, 1965, P. oteroi Arya, 1992 and P. mulloidi Imam, Tawfik et Abdel Hady, 1982, are designated as species inquirendae and incertae sedis. The finding of P. sphyrnae in Australian waters represents a new geographical record of this parasite outside the Atlantic Ocean. Key words: Parasitic nematode, Trichinelloidea, Habronematoidea, Sphyrnidae, Australian waters During investigations into parasites of hammerhead sharks (Sphyrnidae, Carcharhiniformes) in Australian waters, carried out by the junior author (D. P. Barton) in 2015–2018, two species of adult nematodes were recorded from the spiral valve of the scalloped hammerhead Sphyrna lewini (Griffith et Smith) and the great hammerhead Sphyrna https://www.nespmarine.edu.au/document/description-piscicapillaria-bursata-sp-nov-capillariidae- and-redescription-parascarophis Page 2 https://link.springer.com/article/10.2478%2Fs11686-019-00058-4 POSTPRINT mokarran (Rüppel). Their closer examination showed that they represented a new species of the genus Piscicapillaria Moravec, 1982 (Capillariidae) and the already known, but inadequately described, type species of the genus Parascarophis Campana-Rouget, 1955 (Cystidicolidae). Results of this study are presented below. Both species of hammerheads examined have a circumpolar distribution in coastal warm temperate and tropical seas (Froese and Pauly 2018). MATERIALS AND METHODS Sharks were collected from 10 localities off the Northern Territory, New South Wales and Queensland coast of Australia. Sharks were collected as part of various other projects and made available for parasite examination. The sharks collected from northern New South Wales (NSW) were caught in five bather-protection gill-nets deployed off Ballina and Evans Head during the austral summer of 2016/2017. Dead great hammerheads were removed from the gill-nets and frozen whole. Sharks were defrosted and the stomach and spiral valve were removed, placed in bags and refrozen. Sharks collected from Queensland (Qld) (Ayr and Cleveland Bay (NO) and Cairns (FNO)) and the Northern Territory (NT) were comprised of by-catches of regional commercial fishers and were frozen whole prior to dissection. The NT specimens were grouped by location: Gulf of Carpentaria (GoC), Arafura Sea (ARF), North NT (NNT) (offshore locations between the Tiwi islands and the Wessel Islands), Darwin (DRW), Joseph Bonaparte Gulf (JBG) and the Timor Sea (TS). Some specimens were defrosted and processed, with the digestive system bagged and refrozen. Other specimens were processed at the time of dissection. https://www.nespmarine.edu.au/document/description-piscicapillaria-bursata-sp-nov-capillariidae- and-redescription-parascarophis Page 3 https://link.springer.com/article/10.2478%2Fs11686-019-00058-4 POSTPRINT Independent of the source of the sharks, processing of specimens remained the same. The digestive system was separated at the junction of the stomach and the spiral valve. The stomach was opened longitudinally on a tray and examined for dietary components and parasites. In stomachs with a large quantity of food or liquid, the stomach and its contents were placed into a jar and washed. The spiral valve was opened longitudinally, washed and examined for parasites. The washings for each section were searched using a dissecting microscope. The nematodes obtained were washed in physiological saline and then fixed and preserved in 70% ethanol. For light microscopical examination, the nematodes were cleared using glycerine. Drawings were made with the aid of a Zeiss drawing attachment. Specimens used for scanning electron microscopy (SEM) were postfixed in 1% osmium tetroxide (in phosphate buffer), dehydrated through a graded acetone series, critical-point-dried and sputter-coated with gold; they were examined using a JEOL JSM-7401F scanning electron microscope at an accelerating voltage of 4 kV (GB low mode). All measurements are in micrometres unless otherwise indicated. The fish nomenclature adopted follows FishBase (Froese and Pauly 2018). RESULTS Capillariidae Railliet, 1915 Piscicapillaria bursata sp. n. Figs. 1–3 Description: Small, filiform nematodes with finely transversely striated cuticle (Figs. 2A, C–F, 3A, F). Two lateral bacillary bands extend along body (Fig. 3E, F). Oral aperture https://www.nespmarine.edu.au/document/description-piscicapillaria-bursata-sp-nov-capillariidae- and-redescription-parascarophis Page 4 https://link.springer.com/article/10.2478%2Fs11686-019-00058-4 POSTPRINT terminal, roughly oval, oriented dorsoventrally, surrounded by 2 elevated lips almost connected at angles of mouth; outer margin of lips rounded (Figs. 1B, 2A, 3B). Stylet absent. Mouth surrounded by 12 cephalic papillae arranged in 2 circles, each consisting of 6 papillae, and pair of small lateral amphids (Figs. 1B, 2A, 3B, D). Muscular oesophagus long, narrow (Fig. 1A). Stichosome consisting of single row of approximately 50 elongate stichocytes. Stichocytes in anterior part of stichosome formed by elongate stichocytes with little visible nuclei; these stichocytes are all alike, their anterior margin being dome-shaped. In posterior part of stichosome, two long, more granular stichocytes with numerous (4–16) transverse annuli and well visible large nuclei alternating always with one very short stichocyte also with large nucleus (Fig. 1F, G). Two wing-like glandular cells present at level of oesophago- intestinal junction (Fig. 1F). Male (1 specimen, holotype): Length of body 6.75 mm, maximum width 42. Width of lateral bacillary bands at level of posterior end of oesophagus 15. Length of entire oesophagus 3.74 mm, representing 55% of body length. Length of muscular oesophagus 330, of stichosome 3.41 mm; number of stichocytes probably 52. Nerve ring situated 87 from anterior extremity. Spicule canal well developed, 117 long (Fig. 1E). Spicule well sclerotised, 330 long and 6 wide, its proximal end nonexpanded, distal end rounded; surface of spicule smooth, without rough transverse grooves (Fig. 1E, H, I). Spicular sheath invaginated, with numerous small spines (Fig. 1D, E). Posterior end of body provided with fairly long, rounded membranous bursa supported by conical dorsal caudal projection and, on each side, by wide, posteriorly directed ray; large spherical papilla present at base of each of them (Figs. 1C, D, 2C–F). Female (1 complete ovigerous specimen, allotype, and 1 incomplete paratype specimen, both from S. mokarran; measurements of latter in parentheses. Measurements of 2 ovigerous, 1 complete and 1 incomplete, paratype specimens from S. lewini in brackets): https://www.nespmarine.edu.au/document/description-piscicapillaria-bursata-sp-nov-capillariidae- and-redescription-parascarophis Page 5 https://link.springer.com/article/10.2478%2Fs11686-019-00058-4 POSTPRINT Length of body 21.26 (-) [12.80] mm, maximum width 81 (105) [69–75]. Width of lateral bacillary bands at level of posterior end of oesophagus 24 (30) [18]. Length of entire oesophagus 5.77 (6.94) [5.30–5.56] mm, representing 27% (-) [43%] of body length. Length of muscular oesophagus 366 (333) [318–339], of stichosome 5.40 (6.61) [5.30–5.56] mm; number of stichocytes approximately 48 (45) [50]. Nerve ring situated 93 (72) [96] from anterior extremity. Vulva located